The present invention relates broadly to seals for sealing an assembly including a housing having a bore and a generally annular element received within the bore, and more particularly wherein such assembly is a flowline diverter.
As further described, for example, in U.S. Pat. Nos. 5,890,535 and 6,290,231, flowline diverters are mounted to offshore drilling rigs below the rig floor for use in early stages of drilling. In basic construction, flowline diverters include a tubular support housing and a cylindrical spool. The housing has an axial bore and is mounted below the rig floor. The housing also has a lateral flowline outlet for directing gas, liquid, or other fluid flow when the diverter is closed. The spool is secured to the upper end of a riser, and is lowered through the rotary table of the rig to be received in the housing. The spool has lateral flow openings that align axially with the lateral flowline outlet.
A pair of seals is installed above and below the lateral flowline outlet to seal the spool to the diverter housing. Each of the seals is received in a corresponding gland defined between the bore of the housing and the spool. Passageways are provided in the spool in fluid communication with a corresponding one of the glands to receive a source of fluid pressure, such as hydraulic fluid or another liquid or gas media, for energizing the seals. As so energized, the seals prevent fluid flow from leaking between the diverter spool and the housing with the seal outer diameter sealing against the bore of the housing and the seal inner diameter sealing against the spool.
Some seals for diverters utilize rigid metal rings or end caps which are bonded to each end of an annular elastomeric body having a pair of annular lips formed along the inner diameter of the seal. The lips are energizable by the source of fluid pressure. The rings are employed to help prevent the seal from being extruded between the diverter bore and body.